// ================================================================================================

// SelectionTracker.cs

//

// Created: 2008.08.04, by Istvan Novak (DeepDiver)

// ================================================================================================

using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using Microsoft.VisualStudio.Shell;

using Microsoft.VisualStudio.Shell.Interop;



namespace VSXtra.Selection

{

  // ================================================================================================

  /// <summary>

  /// This class is a wrapper around the STrackSelection service.

  /// </summary>

  // ================================================================================================

  public class SelectionTracker

  {

    #region Private fields



    private readonly ITrackSelection _TrackSelection;

    private SelectionContainer _Container;



    #endregion



    #region Lifecycle methods



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// Creates a new selection tracker instance.

    /// </summary>

    /// <param name="provider">Service provider to obtain the selection tracker from.</param>

    /// <param name="selectableRO">Is the collection of selectable objects read only?</param>

    /// <param name="selectedRO">Is the collection of selected objects read only?</param>

    // --------------------------------------------------------------------------------------------

    public SelectionTracker(IServiceProvider provider, bool selectableRO, bool selectedRO)

    {

      _TrackSelection = provider.GetService<STrackSelection, ITrackSelection>();

      _Container = new SelectionContainer(selectableRO, selectedRO);

      Unselect();

    }



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// Creates a new selection tracker instance.

    /// </summary>

    /// <param name="provider">Service provider to obtain the selection tracker from.</param>

    // --------------------------------------------------------------------------------------------

    public SelectionTracker(IServiceProvider provider)

      : this(provider, false, false)

    {

    }



    #endregion



    #region Public properties



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// Gets or sets the selection container.

    /// </summary>

    // --------------------------------------------------------------------------------------------

    public SelectionContainer Container

    {

      get { return _Container; }

      set { _Container = value; }

    }



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// Gets the ITrackSelection object behind this instance.

    /// </summary>

    // --------------------------------------------------------------------------------------------

    public ITrackSelection TrackSelection

    {

      get { return _TrackSelection; }

    }



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// Gets the selected objects.

    /// </summary>

    // --------------------------------------------------------------------------------------------

    public IEnumerable SelectedObjects

    {

      get { return _Container == null ? new ArrayList() : _Container.SelectedObjects; }

    }



    #endregion



    #region Public events



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// The current selection has been changed.

    /// </summary>

    // --------------------------------------------------------------------------------------------

    public event EventHandler SelectionChanged

    {

      add

      {

        if (_Container != null)

          _Container.SelectedObjectsChanged += value;

      }

      remove

      {

        if (_Container != null)

          _Container.SelectedObjectsChanged -= value;

      }

    }



    #endregion



    #region Public methods



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// Gets all the selected objects with the specified type.

    /// </summary>

    /// <typeparam name="T">Type to select.</typeparam>

    /// <returns>A collection of selected object instances with the specified type.</returns>

    // --------------------------------------------------------------------------------------------

    public IEnumerable<T> GetSelectedObjects<T>()

    {

      return SelectedObjects.OfType<T>();

    }



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// Gets the first selected objects with the specified type.

    /// </summary>

    /// <typeparam name="T">Type to select.</typeparam>

    /// <returns>

    /// The first selected object instance with the specified type or null if there is no selected 

    /// object with the specified type.

    /// </returns>

    // --------------------------------------------------------------------------------------------

    public T GetSelectedObject<T>()

    {

      return GetSelectedObjects<T>().FirstOrDefault();

    }



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// Unselects any object selected previously.

    /// </summary>

    // --------------------------------------------------------------------------------------------

    public void Unselect()

    {

      SetSelection(null, null);

    }



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// Sets the provided object as selected and the only selectable.

    /// </summary>

    /// <param name="selectedObject">Object to select.</param>

    // --------------------------------------------------------------------------------------------

    public void SelectObject(object selectedObject)

    {

      ICollection container = new ArrayList {selectedObject};

      SetSelection(container, container);

    }



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// Sets the provided object as selected and the list of objects as selectable.

    /// </summary>

    /// <param name="selectedObject">Object to select.</param>

    /// <param name="selectableObjects">Objects that can be selected.</param>

    // --------------------------------------------------------------------------------------------

    public void SelectObject(object selectedObject, IEnumerable selectableObjects)

    {

      SetSelection(new ArrayList {selectedObject}, ToArrayList(selectableObjects));

    }



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// Sets the list of objects as selected and selectable.

    /// </summary>

    /// <param name="selectedObjects">Objects to select.</param>

    // --------------------------------------------------------------------------------------------

    public void SelectObjects(IEnumerable selectedObjects)

    {

      SetSelection(ToArrayList(selectedObjects), ToArrayList(selectedObjects));

    }



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// Sets the provided objects as selected and the list of objects as selectable.

    /// </summary>

    /// <param name="selectedObjects">Object to select.</param>

    /// <param name="selectableObjects">Objects that can be selected.</param>

    // --------------------------------------------------------------------------------------------

    public void SelectObjects(IEnumerable selectedObjects, IEnumerable selectableObjects)

    {

      SetSelection(ToArrayList(selectedObjects), ToArrayList(selectableObjects));

    }



    #endregion



    #region Private methods



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// Converst an IList to an ArrayList

    /// </summary>

    // --------------------------------------------------------------------------------------------

    private static ArrayList ToArrayList(IEnumerable list)

    {

      var result = new ArrayList();

      foreach (var item in list) result.Add(item);

      return result;

    }



    // --------------------------------------------------------------------------------------------

    /// <summary>

    /// Carries out the selection.

    /// </summary>

    // --------------------------------------------------------------------------------------------

    private void SetSelection(ICollection selected, ICollection selectable)

    {

      if (_Container != null)

      {

        _Container.SelectableObjects = selectable;

        _Container.SelectedObjects = selected;

      }

      if (_TrackSelection != null)

      {

        _TrackSelection.OnSelectChange(_Container);

      }

    }



    #endregion

  }

}